Test Equipment Anonymous (TEA) group therapy thread

[mnementh]

Meets quite a few criteria,
Test equipment tick
Nixie tube tick
Ham related tick
It works tick
Happy camper here

Does need sl weird power supply (220v, we have 240v and with all the solar feed in, it often hits 250v)

West Oz used to be 250v, & plenty of devices with supposedly lower voltage ratings operated merrily for decades.

As factory has pointed out, the thing has adjustable transformer primary taps.
A "234" volt setting will operate ok on 250v "till the cows come home".

Immediately I envisage some content operator in front of his equipment, until a loud 'MOOOO' is heard from the window. In the same moment an evil flash, smoldering sound and thick smoke emanates from the rear of some device!

mnem
Still less brain damage than 4 hours of surfing "funny" cat memes...

[RolandK]

The divide-by-10 circuits in the 1965 Tek 184 use only 3 transistors. How do they do that? Having debugged mine, that's a rhetorical question!

Just wondered how they did it, because with 3 storage-stages you can encode 2^3. So i looked in the schematic. But they used 2 stages: one devide by 2 and one devide by 5. Both use 3 transistors. Or didn't i see something?

[mnementh]

Those funny looking transistor symbols were "the latest & greatest" in the early 1960s, & some early adopters got their fingers burned when they went with them. One such was the Oz electronics mag "Electronics Australia", who adopted them whole-heartedly, only to have to backpedal a while later, when they realised they "went over like a wrought iron hanglider" in industry.

Your frequency counter is only the second time that I saw them used in a commercially produced schematic.The other was when I had to read the schematic of a device produced by "Commonwealth Electronics" for our old aviation regulator, as part of the old "Broadcast Operator's Certificate of Proficiency" practical test.

I think they kept it as "a trap for young players"----but I was an "old player!"

Oh, fuck... those symbols are positively demonic! It's like they're trying to deliberately make the elements as ambiguous as possible!   

Whoever thought that was a good idea needs to be strung up by 'is nutsack... 

mnem
Probably the same dingle who made it normal to diagram all the pins on a IC out of order so the traces would look neater... and who gave us autoroute...

[mnementh]

Not exactly fun with TEA here, but I've had some fun building a simple transistor test adapter for the Tek 577:

Nothing to tell your mother about, just using stuff that was readily available in the stash. No PCB layout, just perfboard, no fancy white solder mask with black silkscreen, just a printed piece of paper.

      

Oooooh... now that one definitely earns the  UGLY ENGINEERING  seal of approval! 

Just please... tack those loose corners down... *cringe*   

mnem
 

[SeanB]

The divide-by-10 circuits in the 1965 Tek 184 use only 3 transistors. How do they do that? Having debugged mine, that's a rhetorical question!

Just wondered how they did it, because with 3 storage-stages you can encode 2^3. So i looked in the schematic. But they used 2 stages: one devide by 2 and one devide by 5. Both use 3 transistors. Or didn't i see something?

Pulse counting, they select the capacitor and resistor values, so that you need a certain number of pulses, before the transistor starts to conduct, blanking the input for the remainder of the pulses. Needs to have very specific input frequencies, and very narrow bounds on component tolerance as well to get it to work, but you can do a divide by n over a small range, providing your input frequency is constant.

[tggzzz]

The divide-by-10 circuits in the 1965 Tek 184 use only 3 transistors. How do they do that? Having debugged mine, that's a rhetorical question!

Just wondered how they did it, because with 3 storage-stages you can encode 2^3. So i looked in the schematic. But they used 2 stages: one devide by 2 and one devide by 5. Both use 3 transistors. Or didn't i see something?

You are constrained by "thinking digital", but it is an analogue circuit. Have a look at the circuit description and waveforms.

[tggzzz]

The divide-by-10 circuits in the 1965 Tek 184 use only 3 transistors. How do they do that? Having debugged mine, that's a rhetorical question!

Just wondered how they did it, because with 3 storage-stages you can encode 2^3. So i looked in the schematic. But they used 2 stages: one devide by 2 and one devide by 5. Both use 3 transistors. Or didn't i see something?

Pulse counting, they select the capacitor and resistor values, so that you need a certain number of pulses, before the transistor starts to conduct, blanking the input for the remainder of the pulses. Needs to have very specific input frequencies, and very narrow bounds on component tolerance as well to get it to work, but you can do a divide by n over a small range, providing your input frequency is constant.

Pretty much, but there is no "blanking".

Once enough glugs of charge have been dumped on the capacitor, the voltage across it rises above a threshold and the capacitor is discharged ready for the next glug.

[Neomys Sapiens]

Not exactly fun with TEA here, but I've had some fun building a simple transistor test adapter for the Tek 577:

Nothing to tell your mother about, just using stuff that was readily available in the stash. No PCB layout, just perfboard, no fancy white solder mask with black silkscreen, just a printed piece of paper.

We wouldn't have bothered. But maybe we should tell YOUR mother about?
** Is it wrong for a mother to be hard on prototyping practices? **

[tggzzz]

Oh, fuck... those symbols are positively demonic! It's like they're trying to deliberately make the elements as ambiguous as possible!   

Whoever thought that was a good idea needs to be strung up by 'is nutsack... 

I haven't seen that symbold for a PNP transistor before. But it is a bog standard circuit, one of the first you learn, so it isn't difficult to work out what the symbols mean.

Quite franky I see far worse every day, with signals flowing from right to left, nets named rather than drawn, and schematic design patterns ignored. At least back then they had the excuse that the design patterns hadn't really been established.

[Neomys Sapiens]

Oooooh... now that one definitely earns the  UGLY ENGINEERING  seal of approval! 

Any connection with those?

https://de1lib.org/book/16993951/083c7a

https://de1lib.org/book/16993944/2af64d
 

[mansaxel]

[...]

Remember that "Ubuntu" is zulu for "I can't install Devuan." 

Installing the Devuan is not the problem, running with it is (for me at least). As an "unlucky one" that has come to Linux only after the "poettering apocalypse" - I know nothing else.
I can make a easily comprehensible, human readable, start "script" to have something autostart on a Debian (or anything that runs the dreaded systemd) -
but on devuan, looking into how one might do it, it leads to a whole rabbit hole of tools and references. (And this is just the first thing I was defeated by that came to mind)
As someone who still relies heavily on google to get around doing stuff on linux (and it's not like it is too easy anway) straying too far from the guarded path leads only to despair...

Ok, System V init, the short course:

Programs have start scripts that do all the housekeeping to start them. Lets take a simple one, and call it the Foo Daemon, food.

The daemon is /usr/local/sbin/food and we want it to start when the computer starts normally.

We start by making a script in /etc/init.d/food :

Code: [Select]

#!/bin/sh

ARGS=" -meals dinner,lunch,breakfast,elevenses"

case $1 in
start)
    /usr/local/sbin/food  ${ARGS}
   ;;
stop)
   pkill food
   ;;
*)
   echo "Usage: $0 start|stop"
   ;;
esac

We make the script executable:

chmod 755 /etc/init.d/food

We decide we will start the script in runlevel 3, so we create a symbolic link in the runlevel 3 directory:

ln -sf /etc/init.d/food /etc/rc3.d/S98food

We want to stop it as we reboot:

ln -sf /etc/init.d/food /etc/rc6.d/K01food

When the computer boots, it will go into runlevel 3, and that is defined by the computer sorting and executing the scripts it finds in /etc/rc3.d; those who start with S are called with an argument of "start", the ones starting with "K" are called with "stop" as argument;

/bin/sh /etc/rc3.d/S98food start

et c...

That's all there's to it. (well actually there's more but that's what you need to know. )

[cyclin_al]

...
The offending device is the Realtek RTL8125 series.  In my case, it is on an ASRock B550 Steel Legend motherboard.
...

"Ubuntu 21.04 wird der RTL8125 nativ vom Kernel 5.10.x unterstützt."


In this version of French that is not used too much in Canada  , it tells us that the Ubuntu 21.04 supports natively the  chip and if you don't have special reasons for to install another Ubuntu version, I would go with this one, making the updates a bit easier.

Also kernel series 5.10 is ancient, I'm always amazed why the desktop distributions are not a bit more agile with the kernel and libraries, but this a whole other can of bird seeds.

Cheers,
DC1MC

It does support it ... now.  We need to be a bit more specific in our version numbers.

I realized that I mixed up my ISO files and had created yet another copy of Ubuntu 20.04.1 on my USB stick. 
So I went back and re-did my USB stick with Ubuntu 20.04.3.
This time the computer could boot from the USB stick with Ethernet.  Yay!    Right, or so I hoped?
Choose to install, carefully selecting to replace Ubuntu 20.04.1 with Ubuntu 20.04.3, and leaving other partitions alone.
On installation, there was an error installing the GRUB package.  Uh oh, this is an important one 
Yep, there is no more bootable partition on the drive 

Unfortunately, it is time to pack up this computer, and what little space remains for my bench.
It is Monday, and now the work computer gets unpacked and takes over the space.

Future project:  wipe the SSD and start over with Win 10 (for SWMBO) dual-boot with Ubuntu 20.04.3 (for the 8 year old)...

[Andrew_Debbie]

12V mini UPS arrived today.  I plan to use this as backup for our broadband router, freeing up a portable battery-inverter I've been using.


Claimed output is 3A 12V.   57.7Wh.   The router draws somewhere around 1.5A.     


Topping up before install.

[Zucca]

I am learning FreeBSD, Linux seems something in that direction (or viceversa....)
Anyway here is what I read to learn FreeBSD

I can't find anything like this for Linux.

Interesing:



Fun fact: DOS stands for Dirty Operating System. Unfortunately true in all regards and levels.... This is the one I know best... poor me.

[med6753]

12V mini UPS arrived today.  I plan to use this as backup for our broadband router, freeing up a portable battery-inverter I've been using.


Claimed output is 3A 12V.   57.7Wh.   The router draws somewhere around 1.5A.     


Topping up before install.

I've considered doing the same but out here in the boonies all utilities are above ground and if the power goes out chances are the in line pole mounted amps for my ISP are going to go out too.

And how long will that UPS power it? My guess is 2 hours or less. I wish my typical power outages were less than 2 hours. 

[mnementh]

   Oooooh... now that one definitely earns the  UGLY ENGINEERING  seal of approval! 

Any connection with those?

   https://de1lib.org/book/16993951/083c7a

   https://de1lib.org/book/16993944/2af64d

 

Awwww, hell no... those are entirely too tidy & organized for a UGLY ENGINEERING  project... 

mnem
...but that won't stop me from snurching them with extreme prejudice!   

[mnementh]

Oh, fuck... those symbols are positively demonic! It's like they're trying to deliberately make the elements as ambiguous as possible!   

Whoever thought that was a good idea needs to be strung up by 'is nutsack... 

I haven't seen that symbold for a PNP transistor before. But it is a bog standard circuit, one of the first you learn, so it isn't difficult to work out what the symbols mean.

Quite franky I see far worse every day, with signals flowing from right to left, nets named rather than drawn, and schematic design patterns ignored. At least back then they had the excuse that the design patterns hadn't really been established.

I shoulda known you ( and/or C ) would be right be along to bust my chops...

no, I'm not talking aboot the circuit. I'm talking about changing what is already a well-designed, high-clarity and established universal symbol (which, from what I can see, does predate this device by at least a decade), which denotes all the pertinent information about the device's elements so they are obvious at a glance, and replacing it with this stupidity which, especially if used in an unfamiliar circuit, will do nothing but cause confusion.

It's like they're deliberately obfuscating the elements of the device with that horrid thing; that is just plain bad engineering.

EDIT: Ehh, okay... counter made in 1965; I guess maybe not that well-established  , but still a horrible choice given that the standardized symbols we use now were already in common use.

mnem

[mnementh]

12V mini UPS arrived today.  I plan to use this as backup for our broadband router, freeing up a portable battery-inverter I've been using.


Claimed output is 3A 12V.   57.7Wh.   The router draws somewhere around 1.5A.     


Topping up before install.

I've considered doing the same but out here in the boonies all utilities are above ground and if the power goes out chances are the in line pole mounted amps for my ISP are going to go out too.

And how long will that UPS power it? My guess is 2 hours or less. I wish my typical power outages were less than 2 hours. 

Maths say ~3.3 hours. More than most underdesk UPS will run your PC, tho.

I usually use a cheap underdesk UPS on my gateway/WiFi router both to eliminate assache disconnects from power hiccups and for power conditioning. I've gotten more than 24 hours out of a 600VA unit; no idea how much is lost in the DC-AC-DC conversion chain.

mnem
*juicy*

[mnementh]

I am learning FreeBSD, Linux seems something in that direction (or viceversa....)   
Anyway here is what I read to learn FreeBSD   I can't find anything like this for Linux.   Interesting:   

Fun fact: DOS stands for Dirty Operating System. Unfortunately true in all regards and levels.... This is the one I know best... poor me.

I thought it stood for Dickbag Operating System. 

[EDIT] I clicked on your link and:   

To give you some idea how daunting this online tome is... I taught myself MS-DOS and GW-BASIC using the OEM Red & Blue handbooks. That FreeBSD HTML doc still gives me PTSD just looking at it.   

mnem
BeOS LIVES: https://en.wikipedia.org/wiki/Haiku_(operating_system)

[tggzzz]

12V mini UPS arrived today.  I plan to use this as backup for our broadband router, freeing up a portable battery-inverter I've been using.

I presume you have one of the new-fangled fibre into the home connections.

Is that UPS sufficient to guarantee connectivity if there is a mains power outage? Or is there some OpenReach equipment in the line that requires local mains power?

I note that, despite Ofcom prodding them,  BT (and others) are conspicuously silent about how emergency alarms would work if the power is out.

[capt bullshot]

12V mini UPS arrived today.  I plan to use this as backup for our broadband router, freeing up a portable battery-inverter I've been using.

I presume you have one of the new-fangled fibre into the home connections.

Is that UPS sufficient to guarantee connectivity if there is a mains power outage? Or is there some OpenReach equipment in the line that requires local mains power?

I note that, despite Ofcom prodding them,  BT (and others) are conspicuously silent about how emergency alarms would work if the power is out.

Not at all, I guess.
Here (tm), it's not spoken out loudly but it's well known if you bother to inform yourself: The nodes that are connecting you to the internet are within the same or nearby street and don't have any kind of UPS. Mobile base stations maybe are somewhat further away, but don't have emergency power, too. So it's a simple forecast what happens to all the emergency calls when you've got a power outage in your village / city. At least a power outage is very seldom here.

[med6753]

12V mini UPS arrived today.  I plan to use this as backup for our broadband router, freeing up a portable battery-inverter I've been using.

I presume you have one of the new-fangled fibre into the home connections.

Is that UPS sufficient to guarantee connectivity if there is a mains power outage? Or is there some OpenReach equipment in the line that requires local mains power?

I note that, despite Ofcom prodding them,  BT (and others) are conspicuously silent about how emergency alarms would work if the power is out.

Not at all, I guess.
Here (tm), it's not spoken out loudly but it's well known if you bother to inform yourself: The nodes that are connecting you to the internet are within the same or nearby street and don't have any kind of UPS. Mobile base stations maybe are somewhat further away, but don't have emergency power, too. So it's a simple forecast what happens to all the emergency calls when you've got a power outage in your village / city. At least a power outage is very seldom here.

It's called being shit out of luck. 

[mansaxel]

12V mini UPS arrived today.  I plan to use this as backup for our broadband router, freeing up a portable battery-inverter I've been using.

I presume you have one of the new-fangled fibre into the home connections.

Is that UPS sufficient to guarantee connectivity if there is a mains power outage? Or is there some OpenReach equipment in the line that requires local mains power?

I note that, despite Ofcom prodding them,  BT (and others) are conspicuously silent about how emergency alarms would work if the power is out.

In short; they don't. Some have GSM/3G/4G backup, though. Then it depends on the resiliency of the local cell net.   Our broadband lastmile provider (which is opto transmission) has about 2h UPS on their active gear. This, sadly enough, has been verified by yours truly.

Edit: I've looked at the genset that powers the cell site we have about 500m from home. There are preparations being enforced and somewhat financed by the regulator. 

[tautech]

Quite fortunate here with our Mom and Pop ISP to be supplying a few of their customers from our 5 GHz 10km p-p link to fiber that as these customers are on different mains supply circuits to us he's installed a nice UPS to keep all his stuff alive over power outages and also our WiFi router.   
Outage = grab iPad like nothing has happened.   

[mnementh]

In short; they don't. Some have GSM/3G/4G backup, though. Then it depends on the resiliency of the local cell net.   Our broadband lastmile provider (which is opto transmission) has about 2h UPS on their active gear. This, sadly enough, has been verified by yours truly.

Edit: I've looked at the genset that powers the cell site we have about 500m from home. There are preparations being enforced and somewhat financed by the regulator. 

Probably still better than GorillaServers' DataCenter. 

mnem